Figure 3.

Competition among polarity clusters in wild-type cells. (a, b) Growth of multiple Bem1-GFP clusters and resolution to a single cluster in wild-type diploid (a, DLY9201) and haploid cells (b, DLY9069). Cells were synchronized by hydroxyurea arrest-release prior to imaging. A residual Bem1-GFP signal at the previous cytokinesis site is also visible at the top (a) or bottom (b) of the cropped frames. t = 0 indicates first detection of multiple polarized signals. (c) Coexistence time of multiple clusters: time between the detection of more than one cluster and the first time frame with only one cluster in diploid rsr1Δ/rsr1Δ (n = 27) and RSR1/RSR1 cells (n = 39). Each dot represents one cell; the line is the average coexistence time. (d) Competition between Bem1-GFP clusters is also observed in unsynchronized RSR1/RSR1 cells. (e) Competition between Bem1-GFP clusters is also observed in latrunculin A-treated RSR1/RSR1 cells lacking F-actin. (f) Latrunculin A-treated RSR1/RSR1 cells sometimes display ‘relocation’ of the Bem1-GFP cluster from one pole to the other. (g) In extreme cases, the Bem1-GFP cluster in latrunculin A-treated cells relocates back and forth repeatedly between the two poles. Scale bars, 2 µm. (Online version in colour.)